/Engine/Source/Runtime/CoreUObject/Public/Blueprint/BlueprintSupport.h
Specialized FDeferredInitializationTracker for tracking deferred Blueprint sub-objects specifically. (every object in DeferredInitializers should be a default sub-object or component template).
struct FDeferredSubObjInitializationTracker : public [FDeferredInitializationTrackerBase](API\Runtime\CoreUObject\Blueprint\FDeferredInitializationTrackerBa-), public [TThreadSingleton< FDeferredSubObjInitializationTracker >](API\Runtime\Core\HAL\TThreadSingleton)